Theory of Dyakonov-Tamm waves at the planar interface of a sculptured nematic thin film and an isotropic dielectric material

TL;DR

This paper develops a theoretical framework for Dyakonov-Tamm surface waves at the interface between an isotropic dielectric and a sculptured nematic thin film, revealing wide propagation directions due to periodic nonhomogeneity.

Contribution

It formulates a boundary-value problem and derives a dispersion equation for Dyakonov-Tamm waves at this interface, highlighting the potential for broad propagation directions.

Findings

Surface waves are Dyakonov-Tamm waves guided by the interface.

The angular domain for propagation can be very wide.

Results support experimental verification and optical sensing applications.

Abstract

In order to ascertain conditions for surface-wave propagation guided by the planar interface of an isotropic dielectric material and a sculptured nematic thin film (SNTF) with periodic nonhomogeneity, we formulated a boundary-value problem, obtained a dispersion equation therefrom, and numerically solved it. The surface waves obtained are Dyakonov-Tamm waves. The angular domain formed by the directions of propagation of the Dyakonov--Tamm waves can be very wide (even as wide as to allow propagation in every direction in the interface plane), because of the periodic nonhomogeneity of the SNTF. A search for Dyakonov-Tamm waves is, at the present time, the most promising route to take for experimental verification of surface-wave propagation guided by the interface of two dielectric materials, at least one of which is anisotropic. That would also assist in realizing the potential of such surface waves for optical sensing of various types of analytes infiltrating one or both of the two dielectric materials.